Trying to figure this out for a game I am playing. Thought It might be fun for someone and it would sure be helpful to me I will put it in the form of a word problem.

A space travelling merchant finds a bargain on a particular ore. He purchases 500 Units of this ore for 85 space bucks per unit. This particular ore when refined breaks down into three different minerals. 500 units of this ore yield 321 units of Mineral X, 128 Units of Mineral Y, And 321 Units of mineral Z. The merchant needs to know how much he is paying per unit of mineral x, y, and z respectively, In order to stream line his operation.

He would also really appreciate an explaination and an equation

Thanks so much!